As a precursor to any explanation on this issue, we must first have a very clear understanding of the concept of marriage in Islam and most people in the world and find out why this question has arisen.

According to the Quran: "It is He [God] who created you from a single soul, and made from it its mate, that he might find comfort with her" (7:189)

Obviously, there are other requirements for a person to fulfill when they decide to get married but Quran names comfort before anything else; that is most probably because the fulfillment of all the other needs also leads to the ease of mind and inner peace.

More interestingly, however, it is not only the holy Quran that says getting married is for the purpose of comfort; having a quick search on the internet makes you realize how all people around the world marry mostly for this emotional purpose, as well:

“…there is an important but neglected positive aspect that explains why people voluntarily enter into commitments like marriage: it is a way of expressing your love and devotion to another person. Not the only way, of course, but a well-established and particularly declarative way…” [1].

Monogamy is the best form of Marriage in Islam

To fulfill this emotional need of a person, the only acceptable form of marriage which is agreed upon by almost all psychologists, and is also recommended by Islam is monogamy. It is within the monogamous type of marriage that all the equal rights of men and women are preserved.

The feelings of love, commitment, loyalty, security, trust, honor, and respect as well as many other benefits [2] can be fully achieved when one has only one spouse.

Why, then, Islam Permits Polygamy for Men?

The reason has been explained in a comprehensive article. Based on what is discussed there, nowhere in the Quran, you can find a verse that suggests or encourages polygamy among men to attain more pleasure or to satisfy their carnal desires; there are no positive or negative comments on this regular unlimited tradition of the Arab culture.

Instead, the holy Quran imposes restrictions upon it and introduces it as a remedy to a social problem, i.e., the excess number of women in need of marriage over marriageable men, like at the time of war, etc.

Why can’t women have multiple husbands and polyandry marriage?

Having discussed the concept of marriage in Islam and the limited law of polygamy which is introduced as an exception in case of special social needs, and nothing against the equality of men and women, do you still find the above question unanswered?

If yes, here are some reasons why polyandry is forbidden for women:

It destroys the family which is the foundation of a healthy society. It is usually NOT easy for a woman to perform her duties as a wife and a mother despite having several husbands.

It is against the nature of women and also inconsistent with men's innate desire for exclusivity and love for his wife and children [3].

It adversely affects women’s health, since women with multiple husbands are more prone to STDs.

It increases sterility among women which will result in population problems.

It may cause identification problems for the conceived child.

It may cause identification problems for the conceived child, which will ultimately lead to legal troubles.

These reasons may clearly show why polyandry is uncommon and frowned upon among Muslims and most people in the world. The Islamic point of view on this issue, however, can be summarized as: “Allah desires ease for you, and He does not desire hardship for you” (2:185), and Allah knows best what is good for you.

References:

1. get married
2. being monogamous
3. women's marriage

children's rights in Islam covers all the years of childhood and infancy and include all the needs of a child in the process of his/her growth

Naming (At birth)

Having a good name is one of the important children's rights in Islam. This is because a good name affects one's mind. A child hears his name day and night; and consequently, the meaning of that name unconsciously strengthens those features which are implied in it.

Therefore, the first duty of a parent towards his/her child is to give him/her a good name at birth. Prophet Muhammad (PBUH&HP) has said: “It is the responsibility of every father to choose a good name for his child "[1].

Male Circumcision (The age of seven days)

According to the researchers, male circumcision reduces many possible diseases in a man's reproductive organ. As one of the children's rights in Islam, it is recommended that the boy be circumcised on the seventh day of his birth. But it is obligatory to circumcise before the boy reaches puberty [i].

Breastfeeding (Birth to 2 years old)

Islam strictly recommends breastfeeding, as one of the most significant children's rights in Islam, besides every day more and more scientific evidence confirms the advantages of this act. Breastfeeding is one of the factors affecting the physical, psychological and ethical characteristics of a baby.

According to the Holy Quran: “Mothers shall breastfeed their children for two whole years…” (2:233). Therefore, it is considered a child's right to be breastfed until the approximate age of two.

It is narrated from Prophet Muhammad (PBUH&HP): “For a child, there is no milk better than the milk of the mother” [3]. 

Children's Rights in Islam for the Infancy and early childhood (Birth to 7 years old)

This theory has been proved that the human mind at the very beginning is quite blank, and it only gradually that starts using the faculties of sight, hearing, etc.

As it is noted in Holly Quran, “God has brought you from the wombs of your mothers while you did not know anything and He gave you hearing and sight and hearts that you may give thanks” (16:78)

Consequently, the atmosphere of family and society continuously influence the child's mind, although he/she is not aware of this process. Children are reflections of their parents. The best way to inculcate good behavior in children is to treat them with good grace.

It is emphasized in Islamic thought that children should be kept in a nice and respectful environment. Prophet Muhammad (PBUH&HP) said: “Respect your children and behave them in a nice manner” [4].

Although there is no compulsion on children to do religious duties, it is praised to gradually give children religious training. The impressions gained in childhood are very difficult to erase, and if respect and love of religion are infused into his/her mind in childhood, he/she will always remain attached to the religion.

In this stage, the best way of familiarizing the child with religious teachings is performing religious duties in front of him; children are the mirrors of their surroundings.

Imam Baqir (AS) said: “When the child reaches three years, teach him seven times to recite la ilahailla ' llah (there is no God but Allah). Then leave him at that till he is three years seven months and 20 days old; then train him to say Muhammad-un rasul-u 'llah (Muhammad is the messenger of Allah). Then leave him at that till he completes four years. Then teach him seven times to say Salla 'llahu ala Muhammadin wa aali Muhammad (Peace be upon Muhammad and the progeny of Muhammad). Then leave him at that till he reaches the age of 5 years; then ask him which one is his right hand and which one is the left. When he knows it, then make him face Qiblah [i] and tell him to do prostration (Sajdah)” [5].

This is to continue until he is six years of age. Then he should be told to pray and taught The Bowing (Ruku) and Prostration (Sajdah).

Through mentioned methods, the children learn their religious duties without coercion and feeling any burden upon themselves.  

Notes:
[i] Imam  Sadeq (AS) said: "Circumcise your sons when they are seven days old as it is cleaner and the flesh grows faster and because the earth hates the urine of the uncircumcised" [2].

References:

1. Al-Hurr al-Aamili , Wasail al-shiah, vol. 2, p. 618.    
2. Al-Kafi   Al-Kalini, Abu-Ja'afar Muhammad Ibn-Yaqub. Al-furu'min al-kafi. Vol. 6 Tehran: Dar al-kutub al-islamiyyah. 1981:34.
3. Mirza Hussayn Nuri ,Mustadrak al-Wasāil, vol.  15, p.156.
4. Muhammad Muhammadi Rayshari,Mizan al-Hikmah, vol, 1 , p. 7109.
5. Ibn-e Fazl-e Tabarsi,Makarim Al Akhlaq, p. 115.